Novel underground drip irrigation tape with anisotropic layered permeable membrane structure and manufacturing method of novel underground drip irrigation tape

Abstract

The invention relates to the technical field of irrigation and water conservancy engineering, in particular to a novel underground drip irrigation tape with a different-direction layered permeable membrane structure and a manufacturing method of the novel underground drip irrigation tape. The radial density variation nanofiber modified layer is combined with the substrate layer, and the radial density variation nanofiber modified layer is sequentially combined with the hydrophilic gradient aperture layer and the hydrophobic gradient aperture layer through a cross-linking agent; the center of the substrate layer is aligned with a water outlet of the irrigation emitter, and the anisotropic layered permeable membrane is combined with the drip irrigation tape through an adhesive, covers a circle along the curved surface of the drip irrigation tape and extends towards two sides by taking the water outlet of the irrigation emitter as the center. The manufacturing method of the drip irrigation tape comprises the following steps: S1, preparing a hydrophilic polymer solution in a gradient manner; s2, preparation of radial density variation nanofibers; s3, modifying the surface of the nanofiber layer; s4, constructing a multi-layer gradient aperture layer; and S5, attaching the drip irrigation tape.

Description

Technical Field

[0001] The invention patent relates to the technical field of farmland water conservancy engineering, and specifically to a new underground drip irrigation drip tape with a heterogeneous layered permeability membrane structure and a manufacturing method thereof. Background Art

[0002] Underground drip irrigation is an advanced water-saving irrigation technology. By burying the drip irrigation pipe in the active layer of the underground crop root system, the water is slowly and evenly infiltrated into the soil through micropores, and directly supplied to the crop roots for absorption. This irrigation method significantly improves the water utilization efficiency, usually up to more than 95%, which is much higher than the traditional sprinkler irrigation and surface irrigation methods. Underground drip irrigation not only effectively reduces surface runoff and deep seepage, but also avoids water evaporation loss, saving water resources to a great extent. In addition, underground drip irrigation can keep the soil surface dry, reduce weed growth, improve the crop growth environment, and thus increase crop yield and quality. In arid and semi-arid areas, underground drip irrigation technology is of great significance to the sustainable development of agriculture and is an indispensable part of modern facility agriculture.

[0003] However, current drip irrigation tape products for underground drip irrigation have the following defects: (1) Negative pressure suction of mud causes blockage of drip irrigation emitters: When the drip irrigation system is turned off, the negative pressure generated in the capillary tube can suck tiny particles in the soil into the emitter through the water outlet of the emitter. After long-term accumulation, these tiny particles will cause the emitter to be blocked. Blockage of the emitter will cause the irrigation water to fail to flow out normally, thereby reducing the irrigation efficiency. In severe cases, the entire system may not work properly or even be scrapped. (2) Root invasion causes blockage of drip irrigation emitters: The roots of crops are hydrophilic and will grow along the path of water infiltration. In underground drip irrigation systems, the water and nutrients released by the drip tape become a powerful inducement for root growth. The roots may directly penetrate the wall layer of the drip tape and enter the interior of the pipe, causing blockage or damage. In addition, the dense growth of roots around the drip tape may also increase the compactness of the soil, affecting the penetration and diffusion of water. This root invasion phenomenon is particularly obvious in soils with sufficient water and rich nutrients, and the continuous supply of water further promotes the active growth of the root system.

[0004] At present, the defects of the above-mentioned underground drip irrigation tape are usually solved from two aspects. On the one hand, the anti-clogging ability is improved by optimizing the hydraulic performance of the flow channel structure through the design of the emitter structure. For example, the drip irrigation emitter flow channel structure design method and its fractal flow channel emitter product disclosed by Li Yunkai et al. of China Agricultural University (application publication number: CN106096179A) adopts arc optimization to optimize the flow channel boundary to achieve the improvement of anti-clogging ability. On the other hand, the purpose of preventing root invasion is achieved by adding drug-type sustained-release preparations to the masterbatch of drip irrigation tape or emitter manufacturing. For example, since the 1990s, Geoflow and Agrifim have produced special emitters for preventing root invasion, and herbicides have been added during their production process. The test results show that this emitter has a good root-repelling effect, but the release rate of the drug is uncontrollable. In order to achieve the purpose of root-repelling, an excessive amount of drug needs to be added.

[0005] Invention patent content

[0006] (I) The problems to be solved by the present invention are: solving the problem of root invasion caused by hydrotropism and blockage of emitters caused by negative pressure mud suction; solving the problem of uneven water distribution in the soil microenvironment near the crop roots caused by the inability to regulate the volume of the moistening body due to point-like wetting of the drip irrigation emitter.

[0007] (II) Technical solution

[0008] A novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure comprises an emitter 1, a pipe wall 2 and a heterogeneous hierarchical osmosis membrane, characterized in that the heterogeneous hierarchical osmosis membrane comprises a base layer 3, a radial density variation nanofiber modified layer 4, a hydrophilic gradient pore layer 5 and a hydrophobic gradient pore layer 6, the radial density variation nanofiber modified layer is combined with the base layer, and is sequentially combined with the hydrophilic gradient pore layer 5 and the hydrophobic gradient pore layer 6 on the radial density variation nanofiber modified layer 4 through a crosslinking agent; the center of the base layer 3 is aligned with the water outlet of the emitter 1, and the heterogeneous hierarchical osmosis membrane is combined with the drip irrigation tape through an adhesive, covers a circle along the curved surface of the drip irrigation tape, and extends to both sides with the water outlet of the emitter 1 as the center.

[0009] The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure is characterized in that the manufacturing method of the drip irrigation tape is as follows:

[0010] S1: Gradient configuration of hydrophilic polymer solution: The hydrophilic polymer solution is configured according to a variety of low concentration and low viscosity gradients;

[0011] S2: Preparation of radial density-varied nanofibers: By controlling the voltage, jet distance and solution flow rate of the electrospinning process, the hydrophilic polymer solution prepared in S1 is injected into the spinneret according to the relative concentration and relative viscosity from high to low, and the nanofiber layer is continuously spun on the substrate material from the center to the edge, so that the pore density of the nanofiber layer increases radially and is evenly combined with the substrate material;

[0012] S3: Surface modification of nanofiber layer: removing impurities on the surface of the radial density variable nanofiber layer and activating the surface functional groups, controlling the reaction conditions to graft a grafting agent containing a sulfonic acid group or a grafting agent that can be converted into a sulfonic acid group onto the membrane surface, and after the grafting reaction is completed, post-treating the membrane to remove unreacted grafting agent and by-products to generate a radial density variable nanofiber modified layer;

[0013] S4: Construction of multi-layer gradient pore size layer: The hydrophilic polymer material and the hydrophobic polymer material are sequentially constructed into a hydrophilic gradient pore size layer and a hydrophobic gradient pore size layer on the radial density variation nanofiber modified layer by using electrospinning technology. During the construction process, the pore density from the hydrophilic gradient pore size layer to the hydrophobic gradient pore size layer is gradually expanded by adjusting the concentration of the porogen. After the construction is completed, a cross-linking agent is used for cross-linking and fixation to stabilize the pore size structure and membrane performance, thereby forming an anisotropic hierarchical osmotic membrane;

[0014] S5: Drip tape bonding: With the drip tape emitter as the center, spray adhesive evenly on the bonding area of ​​the drip tape, and bond it with the heterogeneous layered permeability membrane described in S4 to ensure that the two are bonded flat and tightly, and the center of the base coincides with the emitter, and use a heat sealer to seal the edges firmly.

[0015] Preferably, the shape of the base layer is determined according to the distribution characteristics of the crop root system. The axial length of the base layer corresponding to the taproot crop is shorter than that of the fibrous root crop. The axial length is the length of the base layer along the axial direction of the drip irrigation belt.

[0016] Preferably, the porosity of the radial density-varied nanofiber modified layer (4) gradually increases radially from the center to the edge; the porosity of the hydrophilic gradient pore layer (5) and the hydrophobic gradient pore layer (6) increases toward the outside along the hydrophilic gradient pore layer (5) and the hydrophobic gradient pore layer (6).

[0017] Preferably, the hydrophilic polymer solution in S1 is polyvinyl alcohol or polyacrylic acid; the base material in S2 is polytetrafluoroethylene or polyethersulfone; the hydrophilic polymer material in S4 is polydopamine, the hydrophobic polymer material is polydimethylsiloxane, and the cross-linking agent is glutaraldehyde; the adhesive in S5 is water-based acrylic glue.

[0018] Preferably, the voltage for controlling the electrospinning process in S2 is 22-25 kV, the jet distance is 9-15 cm, and the solution flow rate is 0.6-1.3 mL / h.

[0019] Preferably, the reaction conditions controlled in S3 include temperature, time, pH value, and reactant concentration. The temperature is controlled at 23° C.-33° C., the pH value is adjusted to 5-6, the reactant concentration is regulated to 3.5%-5%, and the reaction time is 1-2 hours.

[0020] The beneficial effects of the present invention are as follows: (1) The multi-layer gradient pore layer and radial density structure break the limitation of the single point water outlet of the underground drip irrigation emitter, forming a cylindrical three-dimensional water outlet, which improves the irrigation uniformity of the crop root microhabitat and the balanced distribution of water in the wet body; (2) The hydrophilic gradient pore layer and the hydrophobic gradient pore layer are combined. After the irrigation is stopped, the residual water in the outer hydrophobic gradient pore layer is more easily absorbed into the soil by the soil capillary force, avoiding problems such as root invasion caused by hydrotropism; (3) The porosity gradient design can flush the blocked materials in the pores caused by negative pressure mud suction from the space with lower porosity to the space with higher porosity through water flow during irrigation, and then discharge them to the outside of the drip irrigation belt, reducing the blockage problem caused by negative pressure mud suction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the patent of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the patent of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of the overall structure provided for an embodiment of the present invention;

[0023] Figure 2 The invention provides a method for manufacturing a drip irrigation tape;

[0024] Icons: 1. Irrigator; 2. Tube wall; 3. Base layer; 4. Radial density-varied nanofiber modified layer; 5. Hydrophilic gradient pore size layer; 6. Hydrophobic gradient pore size layer. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be described clearly and completely in combination with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figure 1-Figure 2 As shown, an embodiment of the present invention provides a novel drip irrigation belt for underground drip irrigation with a heterogeneous layered osmosis membrane structure.

[0027] Embodiment 1:

[0028] A novel underground drip irrigation tape with anisotropic hierarchical osmosis membrane structure includes an emitter 1, a pipe wall 2 and anisotropic hierarchical osmosis membrane, wherein the anisotropic hierarchical osmosis membrane includes a base layer 3, a radial density variation nanofiber modified layer 4, a hydrophilic gradient pore layer 5 and a hydrophobic gradient pore layer 6. The base layer 3 is made of polytetrafluoroethylene material, and the center is aligned with the water outlet of the emitter 1 to ensure that water can directly penetrate into the membrane layer. The radial density variation nanofiber modified layer 4 is closely combined with the base layer 3 through electrospinning technology, and its porosity gradually increases from the center to the edge along the radial direction to improve the uniformity of water diffusion.

[0029] The radial density variation nanofiber modified layer is combined with the base layer, and the radial density variation nanofiber modified layer 4 is sequentially combined with the hydrophilic gradient pore layer 5 and the hydrophobic gradient pore layer 6 through glutaraldehyde as a crosslinking agent; the hydrophilic gradient pore layer 5 and the hydrophobic gradient pore layer 6 are made of polydopamine and polydimethylsiloxane materials respectively. The center of the base layer 3 is aligned with the water outlet of the emitter 1, and the anisotropic hierarchical osmotic membrane is combined with the drip irrigation belt through an adhesive, covering a circle along the curved surface of the drip irrigation belt, and extending to both sides with the water outlet of the emitter 1 as the center.

[0030] Embodiment 2:

[0031] A method for manufacturing a new type of drip irrigation tape for underground drip irrigation with a heterogeneous layered permeation membrane structure:

[0032] S1: Gradient preparation of hydrophilic polymer solution: preparing hydrophilic polymer solution polyvinyl alcohol according to low concentration and low viscosity gradient;

[0033] S2: Preparation of radial density-varied nanofibers: By controlling the voltage of the electrospinning process to 22-25 kV, the jet distance to 9-15 cm, and the solution flow rate to 0.6-1.3 mL / h, the hydrophilic polymer solution prepared in S1 is injected into the spinneret in descending order of relative concentration and relative viscosity, and a nanofiber layer is continuously spun from the center to the edge of the substrate on the polytetrafluoroethylene substrate material, so that the pore density of the nanofiber layer increases radially and is evenly combined with the substrate material;

[0034] S3: Surface modification of the nanofiber layer: irradiate with ultraviolet light at 254 nm for 5 to 30 minutes to remove impurities on the surface of the radial density-varied nanofiber layer and activate the surface functional groups, control the temperature to 23°C-33°C, adjust the pH value to 5-6, and adjust the concentration of the reactants to 3.5%-5%. The reaction time is 1-2 hours, and a grafting agent containing a sulfonic acid group or a grafting agent that can be converted into a sulfonic acid group is grafted onto the membrane surface. After the grafting reaction is completed, the membrane is post-treated to remove unreacted grafting agent and by-products to generate a modified nanofiber layer with radial density variation;

[0035] S4: Construction of multi-layer gradient pore size layer: The hydrophilic polymer material polydopamine and the hydrophobic polymer material polydimethylsiloxane are sequentially constructed into a hydrophilic gradient pore size layer and a hydrophobic gradient pore size layer on the radial density variation nanofiber modified layer by using electrospinning technology. During the construction process, the concentration of the porogen is adjusted by 5%-20% to achieve a gradual expansion of the pore density from the hydrophilic gradient pore size layer to the hydrophobic gradient pore size layer. After the construction is completed, the cross-linking agent glutaraldehyde is used for cross-linking and fixation to stabilize the pore size structure and membrane performance, forming an anisotropic hierarchical osmotic membrane;

[0036] S5: Drip irrigation tape bonding: With the drip irrigation tape emitter as the center, spray the adhesive water-based acrylic glue evenly on the bonding area of ​​the drip irrigation tape, and bond it with the heterogeneous layered osmosis membrane described in S4 to ensure that the two are bonded flat and tightly, and the center of the base coincides with the emitter, and use a heat sealer to seal the edges firmly.

[0037] The above is only a preferred embodiment of the patent of the present invention and is not intended to limit the patent of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the patent of the present invention should be included in the protection scope of the patent of the present invention.

Claims

1. A novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure, comprising a water emitter (1), a pipe wall (2) and a heterogeneous hierarchical osmosis membrane, characterized in that: The heterogeneous hierarchical osmosis membrane comprises a base layer (3), a radial density variation nanofiber modified layer (4), a hydrophilic gradient pore layer (5) and a hydrophobic gradient pore layer (6); the radial density variation nanofiber modified layer (4) is combined with the base layer (3), and is sequentially combined with the hydrophilic gradient pore layer (5) and the hydrophobic gradient pore layer (6) on the radial density variation nanofiber modified layer (4) through a crosslinking agent; the center of the base layer (3) is aligned with the water outlet of the emitter (1); the heterogeneous hierarchical osmosis membrane is combined with the drip irrigation belt through an adhesive, covers a circle along the curved surface of the drip irrigation belt, and extends to both sides with the water outlet of the emitter (1) as the center.

2. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 1 is characterized in that: The manufacturing method of the drip irrigation belt is as follows: S1: Gradient preparation of hydrophilic polymer solution: preparing the hydrophilic polymer solution according to a low concentration and low viscosity gradient; S2: Preparation of radial density-varied nanofibers: By controlling the voltage, jet distance and solution flow rate of the electrospinning process, the hydrophilic polymer solution prepared in S1 is injected into the spinneret according to the relative concentration and relative viscosity from high to low, and the nanofiber layer is continuously spun on the substrate material from the center to the edge, so that the pore density of the nanofiber layer increases radially and is evenly combined with the substrate material; S3: Surface modification of nanofiber layer: ultraviolet irradiation is used to remove impurities on the surface of the nanofiber layer with radial density variation and activate surface functional groups, and the reaction conditions are controlled to graft a grafting agent containing a sulfonic acid group or a grafting agent that can be converted into a sulfonic acid group onto the membrane surface. After the grafting reaction is completed, the membrane is post-treated to remove unreacted grafting agent and by-products to generate a modified nanofiber layer with radial density variation; S4: Construction of multi-layer gradient pore size layer: The hydrophilic polymer material and the hydrophobic polymer material are sequentially constructed into a hydrophilic gradient pore size layer and a hydrophobic gradient pore size layer on the radial density variation nanofiber modified layer by using electrospinning technology. During the construction process, the pore density from the hydrophilic gradient pore size layer to the hydrophobic gradient pore size layer is gradually expanded by adjusting the concentration of the porogen. After the construction is completed, a cross-linking agent is used for cross-linking and fixation to stabilize the pore size structure and membrane performance, thereby forming an anisotropic hierarchical osmotic membrane; S5: Drip tape bonding: With the drip tape emitter as the center, spray adhesive evenly on the bonding area of ​​the drip tape, and bond it with the heterogeneous layered permeability membrane described in S4 to ensure that the two are bonded flat and tightly, and the center of the base coincides with the emitter, and use a heat sealer to seal the edges firmly.

3. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 1 is characterized in that: The shape of the base layer is determined according to the distribution characteristics of the crop root system. The axial length of the base layer corresponding to the taproot crop is shorter than that of the fibrous root crop. The axial length is the length of the base layer along the axial direction of the drip irrigation belt.

4. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 1 is characterized in that: The porosity of the radial density-varied nanofiber modified layer (4) gradually increases radially from the center to the edge; the porosity of the hydrophilic gradient pore layer (5) and the hydrophobic gradient pore layer (6) increases toward the outside along the hydrophilic gradient pore layer (5) and the hydrophobic gradient pore layer (6).

5. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 2 is characterized in that: The hydrophilic polymer solution in S1 is polyvinyl alcohol or polyacrylic acid; the base material in S2 is polytetrafluoroethylene or polyethersulfone; the hydrophilic polymer material in S4 is polydopamine, the hydrophobic polymer material is polydimethylsiloxane, and the crosslinking agent is glutaraldehyde; the adhesive in S5 is water-based acrylic glue.

6. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 2 is characterized in that: The voltage for controlling the electrospinning process in S2 is 22-25 kV, the jet distance is 9-15 cm, and the solution flow rate is 0.6-1.3 mL / h.

7. The novel underground drip irrigation tape with a heterogeneous hierarchical osmosis membrane structure according to claim 2 is characterized in that: The reaction conditions controlled in S3 include temperature, time, pH value, and reactant concentration. The temperature is controlled at 23°C-33°C, the pH value is adjusted to 5-6, the reactant concentration is regulated to 3.5%-5%, and the reaction time is 1-2 hours.

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